Dynamic Response Component Location Active... · 07/16/2006 01:33 PM

07/16/2006 01:33 PMhttp://www.landrovertechinfo.com/extlrprod/frmviewit.jsp?szFrom=doc&iDocCode=276785

Page 1 of 19http://www.landrovertechinfo.com/extlrprod/frmviewit.jsp?szFrom=doc&iDocCode=276785

Published: Jan 26, 2005

Active Stabilization System

Dynamic Response Component Location

NOTE: Left hand drive TdV6 shown, other models similar

Item Part Number Description1 Reservoir

2 RH front stabilizer link

3 Pipe set

4 Lower accelerometer

5 Valve block

6 RH rear stabilizer link

7 Upper accelerometer

8 LH rear stabilizer link

9 Rear actuator and stabilizer bar

10 Dynamic response control module

11 LH front stabilizer link

12 Front actuator and stabilizer bar

13 High pressure hose

14 Pump

15 Return pipe - valve block to reservoir

16 Feed pipe - reservoir to pump

GENERAL



The Dynamic Response system provides improved vehicle handling and ride characteristics and is active for both on andoff-road driving.

The Dynamic Response system uses two accelerometers to detect vehicle cornering forces and inputs from the steeringangle sensor to supply data to a dynamic response control module. The control module then operates solenoid valves in avalve block which apply hydraulic pressure to actuators fitted to the front and rear stabilizer bars. The application ofhydraulic pressure to the actuators applies a specified amount of torque to the stabilizer bars to counteract the corneringforces and minimise vehicle body roll.

The following illustrations demonstrate the difference in body angle between a conventional 'passive' (non-DynamicResponse) stabilizer bar vehicle and a vehicle fitted with the Dynamic Response system.

Conventional 'Passive' Stabilizer Bar

Item Part Number DescriptionA Direction of travel - Right hand bend

B Body roll

C Drive line roll

D Tire squash

E Dampers

F Body roll angle

G Drive line roll angle

H Direction of stabilizer bar twist

Dynamic Response System



Item Part Number DescriptionA Direction of travel - Right hand bend

B Body roll

C Drive line roll

D Tire squash

E Stabilizer bar

F Direction of stabilizer bar twist

G Dampers

H Drive line roll angle

I Reduced body roll with Dynamic Response system

The Dynamic Response system is electrically and hydraulically operated. Electrical and hydraulic operation is controlled bythe Dynamic Response control module which is located on the driver's side 'A' post, behind the instrument panel.

The Dynamic Response system comprises front and rear stabilizer bars with integral actuators, two accelerometers, acontrol module, a hydraulic pump, a valve block and a fluid reservoir.

The Dynamic Response system prevents body roll with cornering forces of up to 0.4 g. From 0.4 g there is a progressiveincrease in body roll but significantly lower than on a 'passive' system. A 'passive' system will have a progressive increasein body roll angle as soon as cornering forces are applied and will have a greater roll angle than the Dynamic Responsesystem for the same cornering force.

The Dynamic Response system can also detect when the vehicle is driven off-road. If off-road conditions are detected andthe vehicle is travelling at 25 mph (40 km/h) or less, the control module will reduce roll compensation. On side slopes ofmore than 11 degrees the Dynamic Response system will switch to a 'locked bars' condition at slow speed.

Lateral acceleration of the body is sensed by two accelerometers and signals from these are transmitted to the controlmodule. The engine driven hydraulic pump supplies a constant hydraulic flow to the valve block. Two directional controlvalves are solenoid operated by the control module and supply hydraulic pressure to the applicable side of each actuator toapply a force equal to and opposite to the force applied to the stabilizer bar. In operation the Dynamic Response systemmaintains the attitude of the vehicle body when cornering.

The Dynamic Response hydraulic system uses a semi-synthetic hydraulic fluid which is the same fluid used in the powersteering system. The total capacity of the Dynamic Response system is 2.50 liters (0.66 US gallons).



CAUTION: The Dynamic Response hydraulic system is extremely sensitive to the ingress of dirt and debris.The smallest amount can cause the system to become unserviceable. It is imperative that the followingprecautions are followed: Dynamic Response components are thoroughly cleaned externally before workcommences All opened pipe and component ports are capped immediately All fluid is stored in clean containers.

In the event of a control module or hydraulic failure the system will 'fail-safe' to a 'locked bars' condition. The 'locked bars'condition will allow the stabilizer bars to operate in a similar manner as conventional 'passive' stabilizer bars. Prolongedcornering forces will allow a progressive increase in roll angle due to hydraulic leakage through the actuators and valveblock. Failures of the system are relayed to the driver by illumination of the air suspension/dynamic response warningindicator in the instrument cluster, an audible warning chime and a message displayed in the instrument cluster messagecenter. Faults are recorded by the control module and can be retrieved using T4.

When the ignition switch is moved to position II, the warning indicator is illuminated for two seconds to check functionality.The warning indicator functionality can also be checked using T4.

T4 must also be used to perform a bleeding procedure after repair or maintenance operations have been performed. This isto ensure that the system is completely free from air. Trapped air in the system can significantly reduce systemperformance.

FLUID RESERVOIR

The fluid reservoir is located in the front right hand side of the engine compartment. The reservoir is attached to the front ofair cleaner housing by two slotted rails which positively locate the reservoir.

The reservoir is a moulded plastic container with a threaded neck which is fitted with a sealed cap. Two connections on thebottom of the reservoir provide for connection of the feed pipe to the pump and the return pipe from the valve block.

A non-serviceable filter assembly is fitted to the base of the reservoir. The filter is made from a fine nylon mesh which ismoulded into the bottom of the reservoir. The filter removes particulate matter from the fluid before it is drawn into the pump.

Upper and lower fluid level marks are moulded onto the reservoir body. The capacity of the reservoir to the upper level markis 0.4 liter (0.11 US gallon).

DYNAMIC RESPONSE PUMP

The Dynamic Response hydraulic pump is located on the right hand side of the engine. The pump is attached to a mountingbracket below the generator on TdV6 engines and above the generator on V8 engines. On both engines the pump is drivenby the accessory drive belt from the crankshaft.



Item Part Number Description1 Cam ring

2 Cylinder housing

3 Inlet port

4 Outlet port

5 Shaft

6 Silencer volume

7 Discharge valve

8 Piston spring

9 Piston

10 Housing



11 Counter balance

12 Pulley attachment flange

The hydraulic pump is driven at approximately 1.7 times crankshaft speed by the auxiliary drive belt. The pump is a radialpiston type which delivers fluid at high pressures.

The radial pump has eight pistons located in bores in a cylinder housing. A balanced central shaft, which is driven by apulley and the auxiliary drive belt, has a cam which operates the pistons as the shaft rotates.

As the cam lobe reaches each piston, the piston is pushed outward, moving the fluid above the piston. The pressure createdby the fluid flow from the bore opens a spring loaded discharge valve. When the valve opens, the now pressurised fluidflows, via the silencer volume area of the cylinder housing, to the outlet port. The silencer volume assists with damping outoperating noise from the pump. When the piston reaches its full stroke, the flow reduces and the discharge valve closesunder spring pressure.

As the cam lobe moves away from the piston, a spring pushes the piston down the bore, creating a vacuum above thepiston. As the piston moves down the bore, ports in the piston are exposed and connect with the fluid inlet port. Thevacuum draws fluid into the piston filling the piston and the chamber above it. As the piston is again pushed upwards, theports in the piston are closed off by the bore and the pressurized fluid opens the discharge valve and flows to the outletport.

The above sequence is applied to each of the eight pistons for every revolution of the shaft and cam. When the engine isrunning the sequence occurs rapidly creating a constant flow of fluid. The fluid flow varies with engine speed and therotational speed of the shaft. The pressure applied to the actuators, created by the flow from the pump, is controlled by thepressure control valve in the valve block.

The pump has a displacement of 6cm3/rev and an operational pressure of 165 bar (2248 lbf/in2). The pump output flowranges from 6.5 l/min (1.7 US Gallons/min) at idle to 10 l/min (2.64 US Gallons/min) at 1000 rev/min and above.

DYNAMIC RESPONSE VALVE BLOCK

The valve block is located below the right hand sill of the body and is secured with three bolts and rubber bushes to captivenuts located in the chassis. The rubber bushes isolate the valve block preventing hydraulic noise from transmitting throughthe body.



Item Part Number Description1 Nut (3 off)

2 O ring (3 off)

3 Directional control valve coils (DCV1 and DCV2)

4 O ring (3 off)

5 DCV1

6 Pressure transducer

7 Mounting bush (6 off)

8 Washer (7 off)

9 Bolt (3 off)

10 Nut



11 O ring

12 High pressure filter

13 O ring

14 Pipe connections

15 Stud (3 off)

16 Pressure control valve

17 O ring

18 Pressure control valve coil

19 DCV2

20 Spacer (3 off)

21 Captive nut (3 off) (chassis mounting)

The valve block directs hydraulic pressure to the actuators via solenoid operated directional control valves. A solenoidoperated pressure control valve regulates the required pressure to the actuators. The three solenoid valves are controlledby signals received from the dynamic response control module. A pressure transducer monitors the pressure generated bythe Pressure Control Valve (PCV). A serviceable high pressure filter is installed into the underside of the valve block andfilters the hydraulic fluid before it reaches the control valves. The filter must be changed at the intervals defined on thevehicle service schedule.

The two Directional Control Valves (DCV's) are fitted to ports in the top face of the valve block. The DCV's are screwed intothe valve block and are sealed with O rings. Each DCV has a solenoid for electrical operation of the valve. The solenoid issealed to the DCV with two O rings and secured with a threaded nut. The nut, coil and O rings are serviceable parts. TheDCV's are non-serviceable and failure of a DCV requires replacement of the valve block assembly.

The PCV is fitted to a port in the rear facing end of the valve block. The PCV is screwed into the valve block and is sealedwith O rings. The PCV has coil for electrical operation which is sealed to the PCV with two O rings and secured with athreaded nut. The nut, coil and O rings are serviceable items. The PCV is non-serviceable and failure of the PCV requiresreplacement of the valve block assembly.

The pressure transducer is located in the forward facing end of the valve block and is sealed with an O ring. The pressuretransducer measures the hydraulic pressure and returns a signal to the Dynamic Response control module.

A high pressure filter locates in a port on the lower face of the valve block. The gauze and fibre filter is sealed in the portwith O rings and is secured with a threaded cap which is also sealed with an O ring. A threaded hole in the lower face of thefilter allows a bolt to be fitted to remove the filter from the port. If a system hydraulic component is replaced, the filter mustalso be replaced.

Four ports are located on the forward facing end of the valve block and two ports on the opposite end. Each port is fittedwith a seal pack which contains two O rings and backing rings. The pipes locate and seal in the seal packs and are securedto the valve block with studs and nuts.

ACTUATORS AND STABILIZER BARS

Two stabilizer bars with integral hydraulic actuators are used for the Dynamic Response system. The actuators apply ahydraulically generated force or rotational torque to the stabilizer bar to oppose lateral forces caused by the vehiclecornering.

Actuator Sectional View



Item Part Number Description1 Air bleed ports

2 Piston

3 Ball screw

4 Stabilizer bar

Each actuator has a piston which is attached to the inner part of a rotor linear ball screw, which is splined to half of thestabilizer bar. The outer part of the ball screw is crimped and welded into a housing which is attached to the other half of thestabilizer bar. As pressure is applied to one side of the piston or the other, the ball screw converts the linear force applied tothe piston into a rotational torque between the two halves of the stabilizer bar.

Front Actuator and Stabilizer Bar



Item Part Number Description1 Hardened washer (4 off)

2 RH stabilizer link

3 Stabilizer bar

4 Chassis mounting brackets

5 Actuator

6 LH stabilizer link

7 Stabilizer bar mounting bush

8 Pipe fluid connections

Rear Actuator and Stabilizer Bar



Item Part Number Description1 RH stabilizer link

2 Stabilizer bar bracket

3 Stabilizer bar mounting bush

4 Actuator

5 Stabilizer bar

6 LH stabilizer link

Two hydraulic connections provide for the attachment of the hydraulic pipes from the valve block. The connections providehydraulic flow to each side of the actuator piston.

The front and rear actuator assemblies are similar in their construction, with the rear actuator being smaller than the front.Each stabilizer bar is made from 34 mm (1.34 in) diameter spring steel bar.

The actuator assembly and the stabilizer bars are not serviceable items. Only the stabilizer bar attachment bushes, bracketsand stabilizer links are serviceable components.

The front stabilizer links are not handed on the front stabilizer bar and are also common to vehicles not fitted with DynamicResponse. The rear stabilizer links are unique to vehicles with Dynamic Response. The Dynamic Response rear links areidentified by a grey color plastic bearing moulding. The passive (non-Dynamic Response) links can be identified by a whitecolored plastic bearing moulding.

The front stabilizer bar and actuator is attached to a chassis strengthening member known as the secondary load path andto the front cross-member. Two serviceable, split rubber bushes are fitted to the stabilizer bar and are located in castbrackets. Each bracket is secured to the secondary load path with two bolts and to the front cross-member with a third bolt.

The rear stabilizer bar and actuator is attached to fabricated brackets which are located on the outside of the chassis sidemembers, forward of the rear wheels.

Two rubber bushes are fitted to each stabilizer bar and are located in clamp brackets. The front and rear bushes andbrackets are not interchangeable.

On both the front and rear stabilizer bars, roll correction force is transmitted to the suspension arm via ball jointed stabilizerbar links. The front links are attached to the front suspension upper arm and the rear links are attached to the rear lowerarm.



Each front stabilizer link is fitted with a hardened steel washer which is located between the stabilizer bar and the link balljoint and the upper arm and the link ball joint. It is important that these washers are in the correct position and the correct,hardened washers are fitted. Failure to fit the washers or using incorrect washers will result in relaxation of the torque on theself-locking nut and damage will be caused to the stabilizer bar, link and suspension upper arm.

SYSTEM PIPES

Fluid is moved through the Dynamic Response system via a series of six pipes and hoses. The pipes are mounted onbrackets at strategic points to provide quiet operation of the system.

The six pipes connecting the pump, reservoir and actuators are one-piece components. If the pipes require replacementduring service, the pipes are supplied individually and are removed and replaced in one piece. The front and rear pipesrequire the body to be lifted slightly to allow access for removal and replacement.

The flexible hose which supplies pressure from the pump to the high pressure pipe is fitted with attenuators. The attenuatorscomprise of tuned lengths of PTFE pipe and restrictors within the flexible hose. The attenuators damp pressure pulsations inthe hydraulic fluid produced by the pump, reducing noise and strain on components downstream. The attenuator is integralwith the high pressure hose and cannot be serviced separately.

CAUTION: Under no circumstances during repairs should clamps be used on the high pressure hose or thefront and rear actuator feed pipes to prevent fluid loss. The use of clamps will damage the pipes and hosesleading to premature failure.

DYNAMIC RESPONSE CONTROL MODULE

The Dynamic Response control module is located on the driver's side 'A' post, behind the instrument panel. The controlmodule is secured to the vehicle body with two screws. Two connectors are located on the rear face of the control moduleand allow for the connection of the harness connectors. The two connectors supply power, ground, signal and sensorinformation to and from the control module for control of the Dynamic Response system.

The Dynamic Response control module receives a power supply from the main relay via fuse 9E in the Battery Junction Box(BJB).

An engine speed signal is transmitted to the control module from the Engine Control Module (ECM) via the high speed CANbus. The engine speed signal is used by the Dynamic Response control module to detect that the engine is running andhydraulic pressure for the Dynamic Response system is available.

A road speed signal is transmitted to the control module from the ABS module on the high speed CAN. A steering anglesignal is transmitted on the high speed CAN bus from the steering angle sensor. The Dynamic Response control moduleuses the road speed and steering angle signals to calculate lateral acceleration and for on and off-road roll compensation.

When reverse gear is selected and reverse wheel rotation is transmitted on the high speed CAN bus, the DynamicResponse system reverts to a 'locked bars' condition. This condition is maintained until reverse gear is deselected and aforward wheel rotation message is transmitted on the CAN bus.

The Dynamic Response control module receives an ignition on signal on the high speed CAN bus. The ignition signal



provides an input into the control module to inform the control module that the ignition switch is in position II. The controlmodule initiates a 250 ms start time which is used to prevent functions operating when the software routines are beinginitialized.

When the ignition on CAN signal is removed, the control module senses that the ignition has been switched off. The controlmodule remains powered for a 30 second period to allow fault information and adaptive values to be stored in the memory.The values and fault information are read by the control module when the ignition is next switched on. The power supply tothe control module is maintained for as long as the main relay remains energized.

The Dynamic Response control module is connected on the high speed CAN bus to the diagnostic socket which allowsdiagnostic interrogation of the control module. The diagnostic socket allows for the connection of T4 to read any stored faultcodes in the control module. The control module can also be updated with revised software using T4 should a softwareupdate be required.

When system faults are detected, the control module issues a message on the CAN bus which is received by the instrumentcluster. The instrument cluster then illuminates the air suspension/Dynamic Response warning indicator as follows:

Minor faults - warning indicator illuminated in an amber color with an applicable message in the message centerMajor faults - warning indicator illuminated in a flashing red color with an applicable message in the message centerand an audible warning. The message will instruct the driver to stop the vehicle immediately or drive with caution.

Two messages relating to Dynamic Response are displayed in the instrument cluster message center:

SUSPENSION FAULT, VEHICLE LEAN, WHEN CORNERINGSUSPENSION FAULT, STOP SAFELY, STOP ENGINE.

The Dynamic Response control module supplies a control current to the Pressure Control Valve (PCV) in the valve block.The current supplied is determined by a number of input signals from the upper and lower accelerometers, road speed,steering angle etc.. The PCV controls the hydraulic pressure supplied to the actuators proportional to the current supplied bythe control module.

Power is supplied to the two solenoid operated Directional Control Valves (DCV) in the valve block by the control module.Together, the two DCV's control the direction of flow of hydraulic fluid to the actuators. When the control module suppliespower to the solenoids the valves open allowing hydraulic fluid to flow to the actuators. When power is removed, the DCV'sclose. DCV1 is left open for left hand corners and DCV2 is opened for right hand corners.

The pressure transducer located in the valve block receives a 5V current from the control module. The transducer measuresthe hydraulic pressures in the range of 0 to 180 bar (0 to 2610 lbf/in2) and returns a linear output voltage to the controlmodule dependant on the hydraulic pressure.

The Dynamic Response control module supplies a 5V current to each of the accelerometers. Each accelerometer iscapable of measuring lateral acceleration in the range of ± 1.11 g. An analogue input to the control module of between 0.5and 4.5V relative to the lateral acceleration sensed is returned by each accelerometer. The control module processes thetwo signals received, together with the steering angle and vehicle speed signals, to produce a 'pure' lateral accelerationsignal which is then used as the main control signal for the Dynamic Response system.

Dynamic Response Control Module Connectors C0647 and C2188 Pin Details

Item Part Number Description



1 Connector C0647

2 Connector C2188

Connector C2188

Pin No. Description Input/Output1 12V battery supply from engine management relay Input

2 Ground

Connector C0647

Pin No. Description Input/Output1 Pressure control valve - Negative Input

2 Pressure control valve - Positive Output

3 to 5 Not used -

6 Direction control valve 1 - Positive Output

7 Direction control valve 1 - Negative Output

8 Direction control valve 2 - Positive Output

9 Direction control valve 2 - Negative Output

10 to 12 Not used -

13 Fluid pressure transducer - Signal 5V supply Output

14 Fluid pressure transducer - Pressure signal Input

15 CAN - High Input/Output

16 CAN - Low Input/Output

17 and 18 Not used -

19 Fluid pressure transducer- Ground Input

20 Lower accelerometer - Ground Input

21 Not used -

22 Lower accelerometer - Signal Input

23 Upper accelerometer - Ground Input

24 Not used -

25 Upper accelerometer - Signal 5V supply Output

26 Lower accelerometer - Signal 5V supply Output

27 Not used -

28 Upper accelerometer - Signal Input

29 and 30 Not used -

Failure Modes

Failures where the vehicle can still be driven safely are indicated by the air suspension/Dynamic Response warningindicator in the instrument cluster illuminating continuously in an amber color. The amber indicator will remain illuminateduntil the ignition is switched off. For all faults, the warning indicator will only illuminate again if the fault is still present.

Failures which require the driver to stop the vehicle immediately are indicated by the air suspension/Dynamic Responsewarning indicator flashing in a red color and an audible warning. This will also be accompanied by an applicable messagedisplayed in the message center.

All faults are recorded by the control module and can be retrieved using T4. T4 provides a description of the fault, possible



causes and corrective action to rectify the fault. The control module can fail to one of two states; 'locked bars' or 'reducedoperation'.

The 'locked bars' condition means that pump flow is directed through the valve block and returns to the reservoir. BothDCV's close, trapping the fluid in the actuators. The fluid can flow from one actuator to the other via the valve block. Thestabilizer bars will perform similar to a conventional stabilizer bar, resisting roll but still allowing suspension articulation.

The 'reduced operation' condition means that the system can still operate, but one of the input signals is not being receivedand so the system performance is not optimum.

If the steering angle sensor develops a fault or is out of calibration, there is a possibility that the dynamic response controlmodule will record a fault code. T4 should be used to check for fault codes and the adaptive data should be cleared byresetting the fault codes in the control module after the steering angle sensor has been recalibrated. For additionalinformation, refer to Anti-Lock Control - Traction Control (206-09A Anti-Lock Control - Traction Control)

ACCELEROMETERS

Two accelerometers are used; an upper and a lower. Both accelerometers are identical in their construction.

The lower accelerometer is secured to the underside of the vehicle floor, on the right hand inner sill panel, below the frontdoor. The upper accelerometer is secured to a bracket on the body roof panel, in a central position at the top of thewindscreen.

The lower accelerometer is the primary sensor used to measure lateral acceleration of the vehicle for roll control. The upperaccelerometer is used by the Dynamic Response control module for roll correction and fault detection in conjunction with thelower accelerometer.

Each accelerometer is a capacitive acceleration sensor and operates on a 5V supply from the dynamic response controlmodule. The upper and lower accelerometers can measure acceleration in the range of ±1.11 g and return an output to thecontrol module of between 0.5 and 4.5V.

Failures of an accelerometer are recorded by the control module and can be retrieved using T4. A special tool is required toremove and replace the accelerometer in the mounting bracket.

HYDRAULIC CIRCUIT DIAGRAM



Item Part Number Description1 Hydraulic pump

2 Attenuator hose


4 Directional control valve 2

5 Front actuator assembly

6 Rear actuator assembly

7 Directional control valve 1

8 Valve block

9 Pressure Control Valve (PCV)

10 High pressure filter

11 Filter

12 Reservoir

DYNAMIC RESPONSE SYSTEM OPERATION

Vehicle Not Moving

When the engine is running and the vehicle is not moving, both DCV's are closed, locking fluid in each side of the actuatorpiston. The hydraulic pump draws fluid from the reservoir and passes it at very low pressure to the valve block.

Because both DCV's are closed, after the fluid passes through the high pressure filter, it is directed through the PCV to thereservoir.

The PCV is open fully to allow the full flow to pass to the reservoir. The DCV's will remain closed until the control moduledetects a requirement to operate.

Vehicle Moving and Turning Left

When the vehicle is turning left, the accelerometers detect the cornering forces applied and transmit signals to the controlmodule. The control module determines that an opposing force must be applied to the stabilizer bars to counter the



cornering forces. The control module supplies a current to the solenoid of DCV2. Simultaneously, a current is supplied fromthe control module to the PCV which operates to restrict the flow of fluid returning to the reservoir.

The restriction causes the hydraulic pressure in the system to rise and the pressure is sensed by the pressure transducerwhich sends a signal to the control module. The control module determines from the inputs it receives what pressure isrequired and adjusts the pressure accordingly.

The pressure in the system is applied to the piston of each actuator, applying an opposing force to the stabilizer bar andminimizing the cornering effect on the vehicle and maintaining the vehicle attitude. The fluid displaced from the other side ofthe piston is returned to the reservoir via the valve block.

As the cornering force is removed when the vehicle straightens up, the control module opens the PCV to reduce thepressure in the system. The fluid bleeds from the actuator back into the system as the cornering force is reduced, removingthe force applied to the stabilizer bar. When the vehicle is moving in a straight line DCV2 closes.

Vehicle Moving and Turning Right

When the vehicle is turning right, the accelerometers detect the cornering forces applied and transmit signals to the controlmodule. The control module determines that an opposing force must be applied to the stabilizer bars to counter thecornering forces. The control module supplies a current to the solenoid of DCV1. Simultaneously, a current is supplied fromthe control module to the PCV which operates to restrict the flow of fluid through the by-pass gallery.

The restriction causes the hydraulic pressure in the system to rise and the pressure is sensed by the pressure transducerwhich sends a signal corresponding to the pressure to the control module. The control module determines from the inputs itreceives what pressure is required and adjusts the pressure control valve accordingly.

The pressure in the system is applied to the piston of each actuator, applying an opposing force to the stabilizer bar andminimizing the cornering effect on the vehicle and maintaining the vehicle attitude. The fluid displaced from the other side ofthe piston is returned to the reservoir via the valve block.

As the cornering force is removed when the vehicle straightens up, the control module opens the PCV to reduce thepressure in the system. The fluid bleeds from the actuator back into the system as the cornering force is reduced, removingthe force applied to the stabilizer bar. When the vehicle is moving in a straight line DCV1 closes.

Vehicle Moving in a Straight Line

The control module is constantly monitoring the signals received and operates the DCV's and PCV to maintain the vehicleattitude when the vehicle is moving.

Off-Road Driving

Off-road detection is achieved by the control module by monitoring the signals from the upper and lower accelerometers forvarying degrees of body movement. Off-road driving generates differing signals to the accelerometers which in turn producediffering outputs due to their vertical separation and the location of the roll center of the vehicle.

The two signals are passed through a filter to remove any offset caused by the vehicle leaning or the terrain. The controlmodule then uses this signal to calculate the percentage of road roughness.

Below 25 mph (40 km/h) the percentage of road roughness calculated is used by the control module to limit the operation ofthe Dynamic Response system. At speeds above 25 mph (40 km/h) the system disables the percentage road roughnesssignal and full Dynamic Response system assistance is restored. The system is completely inoperative at speeds below 2mph (3 km/h).

Side Slope Detection

The control module uses side slope detection when the upper and lower accelerometers detect an average acceleration ofmore than ± 0.2 g or 11 degrees of side slope and a road speed of less than 25 mph (40 km/h).

When side slope is detected, both DCV's close to provide a 'locked bars' condition. This condition increases stability andgives a constant vehicle response. As the road speed increases up to 25 mph (40 km/h), the level of average lateralacceleration must also increase and be maintained for the system to recognise that the vehicle is on a side slope. If the



side slope angle is steep and the road speed is low, the control module will detect the side slope in a short time.

CONTROL DIAGRAM

Item Part Number Description1 Main relay

2 Fuse 9E (15A)

3 Left front wheel speed sensor

4 Right front wheel speed sensor

5 Left rear wheel speed sensor

6 Right rear wheel speed sensor

7 Yaw rate and lateral acceleration sensor



8 ABS module

9 Instrument cluster

10 Air suspension control module

11 Transfer box control module

12 Engine control module

13 Transmission control module

14 Diagnostic socket

15 Steering angle sensor

16 Dynamic Response control module

17 Pressure Control Valve (PCV) coil

18 Valve block


20 DCV 2 coil

21 DCV 1 coil

22 Lower accelerometer

23 Upper accelerometer

Documents

Dynamic Response Component Location Active... · 07/16/2006 01:33 PM